This invention relates to power-transmitting drive belts, usable for example in automotive engines, power lawn mowers, electric motor-driven fans, washing machine pumps, clothes dryer drums, etc. When used in an automotive engine, the belt transmits the engine's power to auxiliary units, such as an alternator, power steering pump, water pump, power brake pump and air conditioning compressor. The inventive belt is a discontinuous belt having special end connectors for forming a continuous endless belt structure of selective overall length.
The belt structure can be used as an emergency replacement for a broken belt, to thus temporarily service the power drive system until a new permament belt can be obtained. Alternately the inventive belt might be used as a variable length belt structure, providing a range of belt sizes (e.g., 27 inch length or 28 inch length from the same basic belt unit). In the latter usage the belt design could be used to reduce the number of belt sizes in inventory. The "adjustable length" nature of the belt design permits in-service adjustment of the belt to compensate for belt stretching, as occurs during normal operations.
It is already known to provide variable length belts for temporary (emergency) use. One such belt consists of a hollow flexible tube joinable at its ends by means of a short ribbed rod telescoped into the tube ends. The belt can be mounted on a vehicle without tools and without adjusting the auxiliary drive units to take up belt slack. The belt may be trimmed to fit different applications.
A primary disadvantage of this prior art belt is its limited strength and propensity for belt slippage. The belt's circular cross-section does not transmit power as efficiently as a belt having a cross-section mated to the pulley it will be used on. Also, the tube-style belt does not flex evenly about the ribbed rod connector. It is believed that stress on the rod as the tubular belt moves around each pulley would cause the tube to separate from the rod and lengthen the belt. Any lengthening of the belt would cause belt slippage and degraded performance.
To adequately transmit power from power source to the driven unit(s), the belt should have a cross-section mated to the pulley design, e.g., a V cross-section or double V cross-section or flat rectangular cross-section. V-shaped belts transmit power through their nonparallel sides. Flat belts transmit power through their inner faces. In some cases, both the inner side and the outer side of the belt engage a pulley to transmit power; flat belts or double V cross-sectioned belts are often used in such situations.
The known temporary belts, such as the tubular type discussed above, do not operate efficiently on conventional pulleys. The circular cross-section of the tubular belt does not provide sufficient surface area in contact with the pulley to efficiently transmit power. The belt tends to slide and slip the pulley, with consequent frictional heat build-up and belt deteriorization.
Temporary belts having clasp or buckle type connectors have been used. However they cannot be used in place of a double sided belt because the surface with the clasp or buckle will tend to bind in the pulley. If the clasp or buckle is made of hard material, it may nick and damage the pulley. Even a small nick in the pulley can cause excessive belt wear and lead to premature failure.